Heat spreader anchoring &amp; grounding method &amp; thermally enhanced PBGA package using the same

ABSTRACT

A new method and assembly is provided for anchoring the heat spreader of a PBGA package to the substrate thereof. Anchor features are made part of the PBGA package, these anchor features are provided over the surface of the substrate of the PBGA package. The anchor features align with openings created in the heat spreader stand-off, thus allowing for quick and reliable positioning and anchoring of the heat spreader over the surface of the substrate of the package.

BACKGROUND OF THE INVENTION

[0001] (1) Field of the Invention

[0002] The invention relates to the fabrication of integrated circuitdevices, and more particularly, to a method and package for anchoringand grounding of a heat spreader that is used as part of a thermallyenhanced Plastic Ball Grid Array (PBGA) package.

[0003] (2) Description of the Prior Art

[0004] The semiconductor industry has since its inception achievedimprovements in the performance of semiconductor devices by deviceminiaturization and by increasing the device packaging density.

[0005] One of the original approaches that has been used to createsurface mounted, high pin count integrated circuit packages has been theuse of the Quad Flat Pack (QFP) with various pin configurations. For theQFP, closely spaced leads along the four edges of the flat package areused for making electrical connections from where the electricalconnections are distributed to the surrounding circuitry. Theinput/output (I/O) connections that can be made to the QFP are thereforeconfined to the edges of the flat package, which limits the number ofI/O connections that can be made to the QFP even in applications wherethe pin to pin spacing is small. The QFP has found to be cost effectivefor semiconductor devices where the device I/O pin count does not exceed200. To circumvent this limitation, a new package, a Ball Grid Array(BGA) package has been introduced. For the BGA package, the electricalcontact points are distributed over the entire bottom surface of thepackage thereby eliminating the restriction of having I/O connects onlyaround the periphery of the package. More contact points with greaterspacing between the contact points can therefore be allocated across theBGA package than was the case with the QFP. The contact points that areused for the BGA package are typically solder balls that have the addedadvantage of facilitating flow soldering of the package onto a printedcircuit board.

[0006] Prior Art substrate packaging uses ceramic and plastic BGApackaging. Ceramic substrate packaging is expensive and has proven tolimit the performance of the overall package. Recent years have seen theemergence of plastic BGA packaging; this packaging has become the mainstream design and is frequently used in high volume BGA packagefabrication. The Plastic substrate BGA (PBGA) package performssatisfactorily when used for low-density flip-chip IC's. If the numberof pins emanating from the IC is high, that is in excess of 350 pins, orif the number of pins coming from the IC is less than 350 but therequired overall package size is small, or if the chip power dissipationis high (in excess of 4 Watts per chip), the plastic structure becomescomplicated and expensive.

[0007] The invention addresses concerns of heat spreader anchoring andgrounding of thermally enhanced PBGA packages that in addition providesadvantages of electrical performance and advantages of assembly whilethe package meets conventional manufacturing standards.

[0008] U.S. Pat. No. 5,616,957 (Kajihari) shows a package with ananchored heat spreader.

[0009] U.S. Pat. No. 5,977,626 (Wang et al.) reveals a thermallyenhanced PBGA and heat spreader design.

[0010] U.S. Pat. No. 6,032,355 (Tseng et al.) and U.S. Pat. No.5,710,459 (Tang et al.) show other heat spreaders.

SUMMARY OF THE INVENTION

[0011] A principle objective of the invention is to provide improvedanchoring and positioning of a heat spreader onto the substrate of thePBGA package by the use of pre-formed anchoring posts on the surface ofthe substrate.

[0012] Another objective of the invention is to provide for accurateplacement of the heat spreader over the surface of the substrate.

[0013] Yet another objective of the invention is to provide for improvedplanarity of the heat spreader and the therewith associated substrate,thereby avoiding mold flashing or bleeding into exposed portions of theheat spreader.

[0014] A still further objective of the invention is to provide a methodthat prevents direct grounding between a ground pad on the surface ofthe substrate of the package and a lower surface of the heat spreader ofthe package.

[0015] In accordance with the objectives of the invention a new methodand assembly is provided for anchoring the heat spreader of a PBGApackage to the substrate thereof. Anchor features are made part of thePBGA package, these anchor features are provided over the surface of thesubstrate of the PBGA package. The anchor features align with openingscreated in the heat spreader stand-off, thus allowing for quick andreliable positioning and anchoring of the heat spreader over the surfaceof the substrate of the package.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a cross section of a conventional PBGA package.

[0017]FIG. 2 shows a cross section of a conventional method ofconnecting a heat spreader to a substrate.

[0018]FIG. 3 shows a cross section of the method of the invention ofconnecting a heat spreader to a substrate.

[0019]FIG. 4 shows a cross section providing detail of the anchoringfeature of the invention of connecting a heat spreader to a substrate.

[0020]FIG. 5 shows a cross section of the anchoring feature of theinvention, whereby optionally a layer of thermally conductive materialis provided.

[0021]FIG. 6a shows a cross section of the conventional method ofsecuring a heat spreader over a substrate.

[0022]FIGS. 6a through 6 c show examples of the method of the inventionof anchoring a heat spreader over the surface of a substrate, thesubstrates of the two representations are different.

[0023]FIGS. 7a through 7 g show a first flow of creating a PBGA packageusing the anchoring method of the invention, this first methodincorporates enhancing the conventional die attach tool.

[0024]FIGS. 8a through 8 f show a second flow of creating a PBGA packageusing the anchoring method of the invention, this first methodincorporates enhancing the conventional heat spreader attach tool.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] For purposes of clarity and reference, a prior art heat spreaderinterconnect methodology for thermally enhanced PBGA package will firstbe discussed using the cross section shown in FIG. 1. For applicationswhere the die-up method of mounting is applied and where the device doesnot meet thermal requirements, the die-down method is frequently usedwhereby substrates are used that have been provided with metalheat-distribution surfaces (heat slugs). A die-down BGA packagetypically has better thermal performance than the die-up PBGA package,since the heat that is generated in the die can be dissipatedeffectively from the backside of the die to the metal heat slugs.However, the assembly cost for this die-down arrangement is considerablyhigher than for the die-up method of mounting semiconductor devices.

[0026] Shown in the cross section of FIG. 1 are the following elementsof a die-up thermally enhanced PBGA package:

[0027]10, the semiconductor die of the thermally enhanced PBGA package,mounted over the surface of substrate 12

[0028]12, a substrate or semiconductor die mounting support; it must beunderstood that conventionally substrate 12 is used for the creation ofmultiple, complex and overlying layers of interconnect traces; theseinterconnect traces have not been highlighted in the cross section ofFIG. 1 and essentially connect contact points or contact pads that areprovided over a first surface of substrate 12 with contact points orcontact pads that are provided over a second surface of substrate 12;examples of contact pads over a first surface of substrate 12 have beenprovided with contact pads highlighted as 22, examples of contact padsover a second surface of substrate 12 have been provided with contactpads highlighted as 24 and 26

[0029]14, the heat sink of the package

[0030]16, a first solder mask layer, typically comprising a patternedand etched layer of dielectric, with openings that align with thecontact pads 22; first solder mask 16 is created over a first surface ofsubstrate 12

[0031]18, a second solder mask layer, typically comprising a patternedand etched layer of dielectric, with openings that align with the coppertraces 24; second solder mask 18 is created over a second surface ofsubstrate 12

[0032]20, interconnect vias provided through substrate 12, creatingelectrical interconnects between contact pads on a first surface ofsubstrate 12 and contact pads on a second surface of substrate 12

[0033]22, conductive traces or contact pads on a first surface ofsubstrate 12; conductive traces 22 are connected to traces 26 by meansof vias 20 or by means of other interconnect traces (not shown) that arepart of the substrate 12

[0034]24, ground pads provided over a second surface of substrate 12;these ground pads 24 are the physical interfaces between the heatspreader 14 and the substrate 12

[0035]25, adhesive glue that is conventionally provided over the surfaceof ground pads 24 for positioning and interfacing with the heat spreader14

[0036]26, contact points provided over the second surface of substrate12

[0037]28, solder balls for further interconnect (not shown) of thepackage that is shown in cross section in FIG. 1 with surroundingelectrical circuitry or electrical components (not shown); of the solderballs that are shown in the cross section of FIG. 1, it must be notedthat some of these solder balls, such as solder ball 28, do notpenetrate through the layer 16 and therefore do not make directelectrical contact with points of electrical contact provided in or onthe first surface of substrate 12; other solder balls, such as solderball 28′, completely penetrate through the solder mask 16 and thereforemakes contact with conductive traces over the surface of the substrate12; other solder balls again, such as solder balls 28″, partiallypenetrate through the solder mask 16 and make contact with contact pads22 provided over a first surface of substrate 12

[0038]30, a layer of thermally conductive adhesive interfacing betweendie 10 and the second surface of substrate 12

[0039]32, points of electrical contact provided over the active surfaceof semiconductor die 10

[0040]34, bond wires for the interconnection of die 10 to contact pads26 provided over a second surface of substrate 12

[0041]36, a mold compound formed over the surface of the structure,which further also surrounds bond wires 34.

[0042] Conventional methods that are applied for the improvement ofthermally enhanced PBGA packages concentrate on:

[0043] increasing the density of the copper that is used in the creationof the substrate of the package

[0044] including an increasing number of metal layers in the substrateof the package

[0045] applying methods of enhanced integration of the heat spreader ofthe package into the package, typically using an adhesive for thispurpose

[0046] increasing the thickness of the metal layers in the substrate ofthe package, and

[0047] adding more thermally conductive parts, vias and solder balls tothe substrate of the package, specifically to surface areas of thesubstrate that align with the thereover mounted semiconductor die of thepackage.

[0048] Specifically highlighted in the cross section of FIG. 1 are theheat spreader standoff features 38 of the heat spreader, which form thesurfaces and method of interfacing the heat spreader 14 with thesubstrate 12 of the PBGA package. Heat spreader 14 may comprise metal ofmay comprise thermally conductive epoxy.

[0049] One of the commonly experienced problems using a PBGA packagethat has been shown in cross section in FIG. 1 is highlighted in thecross section of FIG. 2. Specifically highlighted in the cross sectionof FIG. 2 are:

[0050]25, the adhesive glue, which may be conductive or nonconductive,that is, as previously indicated, provided over the surface of theground pads on which the heat spreader rests

[0051]27, a degree of non-planarity, which conventionally is encounteredin the surface of heat spreader 14 due to a number of influences ofstress and lack of planarity of supporting surfaces in addition tothermally introduced stress in the heat spreader. In the presence of thenon-planarity 27 it is to be expected that uneven stress is present inthe contact points 25 between the heat spreader 14 and the underlyingground pads 24 (FIG. 1), causing mold flashing or bleeding of the moldcompound. In the absence of an even joining, a joining that must bealike for both intersects between the heat spreader 14 and the adhesiveglue 25, the mold 36, FIG. 1, surrounding the semiconductor device 10and the heat spreader 14 is prone to be not evenly distributedsurrounding the die 10 and the heat spreader and can significantlyescape from under the heat spreader 14 and spread out over thesurrounding substrate 12.

[0052]FIG. 3 is a cross section that shows contact points 29, thecontact points of the invention, between the heat spreader 14 and theunderlying substrate 12. The main reason for showing the cross sectionof FIG. 3 is to highlight that the non-planarity 27, FIG. 2, of theconventional method of mounting the heat spreader has been eliminatedusing contact points 29 of the invention. This will be explained indetail following. The application of contact points 29 must concurrentlyprovide for openings in the lower portions of the heat spreaderstand-off 38 where the heat spreader stand-off 38 interfaces with theunderlying substrate 12. In the absence of such openings, the contactpoints 29 would be of little value since the absence of such openingswould inhibit the penetration of contact points 29 into the stand-off 38of the heat spreader.

[0053] The contact points 29, also referred to as anchor posts can becreated using epoxy to which traces of silver have been added or solderpaste or a solid metal.

[0054]FIG. 4 shows a cross section of the section 38, FIG. 1, the heatspreader standoff of the heat spreader 14, which highlights:

[0055] a first surface of the heat spreader 14 is seated directly over asecond surface of the substrate 12

[0056] no adhesive glue is provided in the interface between the heatspreader 14 and substrate 12

[0057] the heat spreader stand-off 38, and therewith the heat spreader14, a seated over the second surface of substrate 12 by means of apositioning and anchoring post 31 that is pre-formed over the surface ofsubstrate 12

[0058] anchoring post 31 is centered with respect to and insertedthrough an opening 33 that has been provided for this purpose in theheat spreader stand-off 38

[0059]35 highlights the consistent seating height of the heat spreader14, which is made possible by the direct contact between the heatspreader stand-off post 38 and the substrate 12, without any interveninglayers of glue, paste and the like.

[0060]FIG. 5 shows a cross section this is the cross section of FIG. 4with the addition of an optional layer 37 of electrically and/orthermally conductive material. This optional layer 37 provides forfirmer seating and locking of the standoff 38, in addition layer 37enhances thermal conduction from the heat spreader 14 to the surface ofsubstrate 12.

[0061] This optional layer 37 can be deposited using a material such asepoxy to which traces of silver have been added or solder paste or asolid metal.

[0062] The cross section of FIG. 6a shows a conventional electricallyconductive path between the heat spreader 14 and the underlyingsubstrate 12, as follows:

[0063] from a second surface 46 of the heat spreader 14 to

[0064] the conductive glue 25 to

[0065] the metal ground pad 24 to (not shown)

[0066] a ground-ring that is conventionally provided as a component ofsubstrate 12.

[0067]FIGS. 6b and 6 c provide further detail regarding the heatspreader anchoring of the invention by highlighting the followingelements of this arrangement:

[0068]14, the heat spreader, this heat spreader may be created usingmetal over the surface of which is coated a layer of nickel or therewithelectrically and thermally equivalent material

[0069]39, the conductive anchor of the invention; this anchor ispreformed over the surface of the metal ground pad 24 and therewith overthe surface of substrate 12; anchor 39 may be created using an epoxy towhich traces of silver are added or solder paste or a solid metal

[0070]38, the heat spreader stand-off

[0071]24, a metal ground pad that is connected to a ground plane; theground plane may be provided in a second (or upper) surface of thesubstrate 12 or in an inner ground plane (not shown) for substrates thatcomprise multiple layers of interconnect metal

[0072]12, the substrate of the package

[0073]41, a plated through hole

[0074]40, a layer of a non-conductive material, created over the firstsurface of the heat spreader 14 by coating or by depositing orchemically treating the first surface of heat spreader 14 with anon-conductive material; this layer provides a first surface 40 of heatspreader 14 that is electrically nonconductive

[0075]37, a layer of electrically conductive material provided over theconductive anchor post 39, and

[0076]40, the non-conductive first surface of heat spreader 14.

[0077]FIG. 6c shows a cross section that further illustrates the use ofa substrate 12 wherein multiple layers of conductive interconnects havebeen provided, specifically layers 43, 45 and 47, of which one or moremay be used as signal interconnects or ground planes or power lines andthe like. A plated through hole 41′ has also been highlighted in thecross section of FIG. 6c. Specifically, from the cross section that isshown in FIG. 6c it is clear that the path of electrical conduction forthis cross section is as follows:

[0078] from the second or upper surface 42 of the heat spreader 14 to

[0079] the conductive material (not shown) deposited over the secondsurface of heat spreader 14 to

[0080]37, the layer of conductive material deposited over the anchor 39to

[0081] the conductive anchor 39, the anchor posts of the invention,comprising conductive material, that have been created over the firstsurface of heat spreader 14 to

[0082] the ground pad 24 to

[0083] plated through hole 41′ to

[0084] a thermally conductive layer, such as layer 43, provided as alayer of substrate 12.

[0085]FIGS. 7a through 7 g and 8 a through 8 f are provided to show theheat spreader attach processing steps of the invention before themolding is applied, these two figures are differentiated as follows:

[0086]FIGS. 7a through 7 g show the indicated flow, implemented byenhancing the die attach machine, and

[0087]FIGS. 8a through 8 f show the indicated flow, implemented byenhancing the conventional die heat spreader attach machine.

[0088] The processing flow that is shown in FIGS. 7a through 7 g, whichcomprises enhancing the die attach machine, will be highlighted first,as follows:

[0089] 1. FIG. 7a, step 1, anchor posts 39 (see also FIGS. 6a and 6 b)are created at the time of die attach or after wire bonding, conductiveepoxy is used for this purpose, dispensed through the dispensing needle50; this cross section shows that the invention can be implemented byenhancing the die attach machine such that the die attach machine can,in addition to and simultaneous with depositing the layer 30 ofthermally conductive adhesive (epoxy) interfacing between die 10 and thesecond surface of substrate 12, also deposit conductive epoxy 39

[0090] 2. FIG. 7b, step 2, this is the step of curing the depositedconductive epoxy 39; this step of curing can be performed inline or as abatch over process

[0091] 3. FIG. 7c, step 3, the wire bonding step, wires 34 are provided,these conductive wires interconnect contact points on the active surfaceof die 10 (not shown) with contact pads (not shown), similar toconductive pads 26 of FIG. 1, provided over the second surface ofsubstrate 12

[0092]4. FIG. 7d, step 4, heat spreader 14 is attached as a firstoperation in a first station of the heat spreader attach tool, using forthis purpose pick & place operation 52

[0093]5. FIG. 7e, step 5, deposit a layer 37 (see also FIGS. 6b and 6 c)of conductive epoxy over the surface of the cured epoxy 39, as a secondoperation in a second station of the heat spreader attach tool, usingdispensing needle 50 for this purpose

[0094] 6. FIG. 7f, step 6, perform epoxy cure, curing the depositedlayer 37 of epoxy, and

[0095] 7. FIG. 7g, step 7, complete the package of the invention byproviding the molding 36 underneath and overlying the heat spreader 14.

[0096] The processing flow that is shown in FIGS. 8a through 8 f, whichcomprises enhancing the conventional die heat spreader attach machine,will be highlighted next, as follows:

[0097] 1. FIG. 8a, step 1, anchor post 39 (see also FIGS. 6a and 6 b) iscreated at the time of wire bonding or after wire bonding, conductiveepoxy is used for this purpose, dispensed through the dispensing needle50; it must be noted in the cross section that is shown in FIGS. 8a,step 1, that the bond wires 34 are present at the time that theconductive epoxy is deposited; this reflects the fact that for the flowthat is shown in FIGS. 8a and 8 b, the conventional die attach machineis not modified and therefore performs only the die attach operationwhich is conventionally followed by wire bond connect 34, providing thecross section that is shown in FIG. 8a, step 1

[0098] 2. FIG. 8b, step 2, this is the step of curing the depositedconductive epoxy 39; this step of curing is a quick or snap cure thatcan be performed in-line

[0099] 3. FIG. 8c, step 3, heat spreader 14 is attached as a firstoperation in a first station of the heat spreader attach tool, using forthis purpose pick & place operation 52

[0100] 4. FIG. 8d, step 4, deposit a layer 37 (see also FIGS. 6b and 6c) of conductive epoxy over the surface of the cured epoxy 39; thiscross section shows that the invention can be implemented by enhancingthe heat spreader attach machine such that the heat spreader attachmachine can, in addition to and following the placement of the heatspreader 14, also deposit conductive epoxy 37

[0101] 5. FIG. 8e, step 5, perform epoxy cure, curing the depositedlayer 37 of epoxy, which can be performed in-line or, step 6

[0102] 6. FIG. 8f, step 6, perform epoxy cure, curing the depositedlayer 37 of epoxy, which can be performed off-line as a batch type ovencuring process, and (not shown)

[0103] 7. complete the package of the invention by providing moldingunderneath and overlying the heat spreader.

[0104] The invention can be summarized as follows:

[0105] the invention provides an improved method of positioning andanchoring of the heat spreader with respect to the underlying substrateby using pre-formed anchoring posts

[0106] the anchoring posts of the invention provide for improvedaccuracy in the placement of the heat spreader over the substrate

[0107] the anchoring posts of the invention provide for improvedplanarity of the surface of the heat spreader with respect to thesurface of the underlying substrate

[0108] the invention provides for the prevention of mold flashing orbleeding by preventing that the mold can escape along the (exposed)surface of the heat spreader

[0109] the invention provides for avoiding direct electrical shortingbetween a ground pad, provided over the surface of the underlyingsubstrate, and the heat spreader since the first or lower surface of theheat spreader is provided with a layer of non-conductive material

[0110] the invention provides for a direct interconnecting conductivepath between a second or upper surface of the heat spreader and a groundplane provided as one of the planes of the underlying substrate; aground pad provided over the second or upper surface of the substrateprovides a direct electrical interface between the heat spreader and thesubstrate, from where the ground connection can be completed withinterconnecting conductive posts between the ground pad and a groundplane of the substrate.

[0111] The processing flows that have been shown in FIGS. 7a through 7 gand 8 a through 8 f can be summarized as follows:

[0112]FIGS. 7a through 7 g, enhancing the conventional die attachmachine, implemented by the sequence:

[0113] 1. die attach

[0114] 2. anchor post creation

[0115] 3. curing of the created anchor posts

[0116] 4. wire bonding

[0117] 5. attaching the heat spreader

[0118] 6. depositing of epoxy over the created anchor (optional)

[0119] 7. curing the epoxy deposited over the anchor posts, and

[0120] 8. providing the mold compound, enclosing the mountedsemiconductor die and partially overlying the heat spreader.

[0121]FIGS. 8a through 8 f, enhancing the conventional heat spreaderattach machine, implemented by the sequence:

[0122] 1. performing conventional steps of die attach and wire bonding

[0123] 2. creating the anchor posts of the invention

[0124] 3. curing the created anchor posts (in-line, snap curing)

[0125] 4. attaching the heat spreader

[0126] 5. depositing of epoxy over the created anchor posts (optional),

[0127] 6. curing the epoxy deposited over the anchor posts, and

[0128] 7. providing the mold compound, enclosing the mountedsemiconductor die and partially overlying the heat spreader.

[0129] Although the invention has been described and illustrated withreference to specific illustrative embodiments thereof, it is notintended that the invention be limited to those illustrativeembodiments. Those skilled in the art will recognize that variations andmodifications can be made without departing from the spirit of theinvention. It is therefore intended to include within the invention allsuch variations and modifications which fall within the scope of theappended claims and equivalents thereof.

What is claimed is:
 1. A method for anchoring a heat spreader of aPlastic Ball Grid Array (PBGA) package to the surface of an underlyingsubstrate of the PBGA package, comprising the steps of: (a) providing asubstrate for a PBGA package, said substrate having been provided withheat spreader anchor posts over the surface thereof, said heat spreaderanchor posts being separated by a first distance; (b) providing a heatspreader for a PBGA package, said heat spreader comprising: (i) ahorizontal portion, being parallel with the surface of said substrate ofsaid PBGA package; (ii) heat spreader stand-off features; (iii) saidheat spreader stand-off features having a contact surface providingcontact between said heat spreader and said substrate; (iv) said contactsurface of said heat spreader stand-off features having been providedwith openings there-through; and (v) said openings provided through saidcontact surfaces being separated by a distance of said first distance;(c) aligning said anchor posts provided over the surface of saidsubstrate with said openings provided through said contact surfaces ofsaid stand-off features of said heat spreader; and (d) inserting saidanchor posts provided over the surface of said substrate into saidopenings provided through said contact surfaces of said stand-offfeatures of said heat spreader, creating anchor posts protruding throughsaid openings provided through said contact surfaces.
 2. The method ofclaim 1, said anchor posts comprising deposits of thermally andelectrically conductive material, said thermally and electricallyconductive material having been cured after deposition thereof.
 3. Themethod of claim 1, said anchor posts comprising a material selected fromthe group consisting of epoxy to which traces of silver have been addedand solder paste and a solid metal.
 4. The method of claim 1, said heatspreader having a first and a second surface, said first surface facingsaid substrate, said first surface having been provided with a layer ofelectrically non-conductive material.
 5. The method of claim 4, saidproviding said first surface of said heat spreader with a layer ofelectrically non-conductive material comprising a method selected fromthe group consisting of coating and depositing and chemically treatingthe first surface of said heat spreader.
 6. The method of claim 1, saidanchor posts having been created applying methods is dispensing orprinting of electrically and thermally conductive material.
 7. Themethod of claim 6, said conductive material comprising epoxy to whichtraces of silver have been added.
 8. The method of claim 1, said anchorposts having been created applying methods of solder bump or contactpoint creation.
 9. The method of claim 1, with additional steps of:depositing a layer of electrically and thermally conductive materialover said anchor posts protruding through said openings provided throughsaid contact surfaces, thereby including a surface area of said heatspreader surrounding said openings provided through said contactsurfaces; and curing said deposited layer of electrically and thermallyconductive material.
 10. The method of claim 9, said electrically andthermally conductive material comprising a material selected from thegroup consisting of epoxy to which traces of silver have been added andsolder paste and a solid metal.
 11. A method for creating a Plastic BallGrid Array (PBGA) package, comprising the steps of: (a) providing a PBGAsubstrate having points of electrical contact over the surface thereof,a layer of thermally conductive adhesive having been provided over thesurface of said substrate, at least one semiconductor device having beenpositioned over the surface of said layer of thermally conductiveadhesive using a die attach process, said positioning of said at leastone semiconductor device being performed such that contact pointsprovided in an active surface of said at least one semiconductor devicebeing exposed and facing away from the surface of said substrate; (b)creating anchor posts over the surface of said substrate, said anchorposts being separated by a first distance; (c) curing said createdanchor posts; (d) electrically connecting said contact points providedin an active surface of said at least one semiconductor device with saidpoints of electrical contact provided over the surface of saidsubstrate, using methods of wire bonding; (e) providing a heat spreaderfor said PBGA package, said heat spreader comprising: (i) a horizontalportion, being parallel with the surface of said substrate of said PBGApackage; (ii) heat spreader stand-off features; (iii) said heat spreaderstand-off features having a contact surface providing contact betweensaid heat spreader and said substrate; (iv) said contact surface of saidheat spreader stand-off features having been provided with openingsthere-through; and (v) said openings provided through said contactsurfaces being separated by a distance of said first distance; (f)aligning said anchor posts provided over the surface of said substratewith said openings provided through said contact surfaces of saidstand-off features of said heat spreader; and (g) inserting said anchorposts provided over the surface of said substrate into said openingsprovided through said contact surfaces of said stand-off features ofsaid heat spreader, creating anchor posts protruding through saidopenings provided through said contact surfaces.
 12. The method of claim11, said anchor posts being created during said die attach process. 13.The method of claim 11, said anchor posts comprising deposits ofthermally and electrically conductive material.
 14. The method of claim11, said anchor posts comprising a material selected from the groupconsisting of epoxy to which traces of silver have been added and solderpaste and a solid metal.
 15. The method of claim 11, said heat spreaderhaving a first and a second surface, said first surface facing saidsubstrate, said first surface having been provided with a layer ofelectrically non-conductive material.
 16. The method of claim 15, saidproviding said first surface of said heat spreader with a layer ofelectrically non-conductive material comprising a method selected fromthe group consisting of coating and depositing and chemically treatingthe first surface of said heat spreader.
 17. The method of claim 11,said anchor posts having been created applying methods is dispensing orprinting of electrically and thermally conductive material.
 18. Themethod of claim 17, said of electrically and thermally conductivematerial comprising epoxy to which traces of silver have been added. 19.The method of claim 11, with additional steps of: depositing a layer ofelectrically and thermally conductive material over said anchor postsprotruding through said openings provided through said contact surfaces,thereby including a surface area of said heat spreader surrounding saidopenings provided through said contact surfaces, thereby using methodsof dispensing or printing; and curing said deposited layer ofelectrically and thermally conductive material.
 20. The method of claim19, said electrically and thermally conductive material comprising amaterial selected from the group consisting of epoxy to which traces ofsilver have been added and solder paste and a solid metal.
 21. Themethod of claim 19, with additional steps comprising molding andencapsulation processes.
 22. A method for creating a Plastic Ball GridArray (PBGA) package, comprising the steps of: (a) providing a PBGAsubstrate having points of electrical contact over the surface thereof,a layer of thermally conductive adhesive having been provided over thesurface of said substrate, at least one semiconductor device having beenpositioned over the surface of said layer of thermally conductiveadhesive using a die attach process, said positioning of said at leastone semiconductor device being performed such that contact pointsprovided in an active surface of said at least one semiconductor devicebeing exposed and facing away from the surface of said substrate, saidcontact points provided in an active surface of said at least onesemiconductor device having been electrically connected with said pointsof electrical contact provided over the surface of said substrate, usingmethods of wire bonding; (b) creating anchor posts over the surface ofsaid substrate, said anchor posts being separated by a first distance;(c) curing said created anchor posts, applying methods of in-line orsnap curing; (d) providing a heat spreader for a PBGA package, said heatspreader comprising: (i) a horizontal portion, being parallel with thesurface of said substrate of said PBGA package; (ii) heat spreaderstand-off features; (iii) said heat spreader stand-off features having acontact surface providing contact between said heat spreader and saidsubstrate; (iv) said contact surface of said heat spreader stand-offfeatures having been provided with openings there-through; and (v) saidopenings provided through said contact surfaces being separated by adistance of said first distance; (e) aligning said anchor posts providedover the surface of said substrate with said openings provided throughsaid contact surfaces of said stand-off features of said heat spreader,using methods of pick and place; and (f) inserting said anchor postsprovided over the surface of said substrate into said openings providedthrough said contact surfaces of said stand-off features of said heatspreader, creating anchor posts protruding through said openingsprovided through said contact surfaces.
 23. The method of claim 22, saidanchor posts comprising deposits of thermally and electricallyconductive material.
 24. The method of claim 22, said anchor postscomprising a material selected from the group consisting of epoxy towhich traces of silver have been added.
 25. The method of claim 22, saidanchor posts being created applying methods of solder bump creation. 26.The method of claim 22, said heat spreader having a first and a secondsurface, said first surface facing said substrate, said first surfacehaving been provided with a layer of electrically non-conductivematerial.
 27. The method of claim 26, said providing said first surfaceof said heat spreader with a layer of electrically non-conductivematerial comprising a method selected from the group consisting ofcoating and depositing and chemically treating the first surface of saidheat spreader.
 28. The method of claim 22, said anchor posts having beencreated applying methods is dispensing or printing of electrically andthermally conductive material.
 29. The method of claim 28, saidconductive material comprising epoxy to which traces of silver have beenadded.
 30. The method of claim 22, with additional steps of: depositinga layer of electrically and thermally conductive material over saidanchor posts protruding through said openings provided through saidcontact surfaces, thereby including a surface area of said heat spreadersurrounding said openings provided through said contact surfaces,thereby using methods of dispensing or printing; and curing saiddeposited layer of electrically and thermally conductive material. 31.The method of claim 30, said electrically and thermally conductivematerial comprising epoxy to which traces of silver have been added. 32.The method of claim 30, said electrically and thermally conductivematerial comprising solder paste.
 33. The method of claim 30, withadditional steps of molding and encapsulation processes.